This is what I have and I love it! I was able to find the HB at 9 wks with my first and then I lent it to one of my girlfriends. She wasnt able to find the HB until about 12 wks. It gave me such peace of mind.
http://www.clinicalguard.com/id/sonoline-b-fetal-heart-doppler-backlight-lcd-3mhz-fda--p-554.html?kw=%7Bkeyword%7D&gclid=COru7rGchrQCFexAMgod3jIAIg